Our general objectives are to gain an understanding of the nature of the metabolic reactions of aromatic hydrocarbons particularly with relation to carcinogenesis and detoxications. Activated derivatives of polycyclic hydrocarbons are reacted with proteins and nucleic acids. The products are analyzed to determine the positions of attack on the molecule. The affects of substitution of hydrocarbon residues on regulatory functions of proteins is under investigation. The affects of photoactivation on the mode of reaction of hydrocarbons is under study.